Slowing device for rheostats.



PATENTED JUNE 4, 1907.

W. B. MASON. SLOWING'DBVIGE FOR RHEOSTATS.

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fray/entana/M/d. ZH tov" APPLICATION FILED JUNE 22. 1906.

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No. 855,797. v PATENTED JUNE 4, 1907.

W. B. MASON. I SLOWING DEVICE FOR RHEOSTATS.

' APPLICATION FILED JUNE 22, 1906.

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WILLIAM B. MASON, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE MASON REGULATOR COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

Specification of Letters Patent.

Patented June 4, 1907.

Applicati m d June 22, 1906. semi No. 322,865.

To all whom it may concern:

Be it known that I, WVILLIAM B. MASON, a citizen of the Jnited States, residing at Boston, county of Suffolk, and Commonwealth of Massachusetts, have invented a certain new and useful Improvement in Slowing Devices for Rheostats, of which the following is a specification, reference being had therein to the accompanying drawings.

In connection with the use of rheostats controlling the supply of fuel to electrically driven pumps and the like, it is frequently desirable that the rheostat arm be moved a short distanceand then stopped or its motion retarded, then moved again and again stopped or retarded, the movement taking place in accordance with the demands made upon the accumulator to which the pump is supplying water. To accomplish this result, I have produced a device which is simple and certain in its operation and which serves to give to the rheostat arm the desired movements.

The invention will be fully understood from the following description taken in connection with the accompanying drawings, and the novel features thereof are pointed out and clearly defined in the claims at the close of the specification.

In the drawings,--Figure 1 is a side elevation of a device embodying my invention, certain parts thereof being in section for greater clearness. Fig. 2 is a plan view showing the arrangement of the levers.

Referring to the drawings and particu larly to Fig. 1,at A there is indicated a large diaphragm chamber connected on the lower side as indicated at B with the system to be controlled by the regulating device. At C is indicateda diaphragm which is movable in response to changes of pressure in the sytsem. Suitably supported in the frame D is a pressure weighing lever E which rests on a knife edge F supported on the diaphragm C. A second knife edge G which is fast to one end of the said lever acts against the urider side of an abutment H on the frame D. The outer end of the said pressure weighing lever E is provided with a weight I. It will be seen, therefore, that an increase in pressure above the predetermined amount for which the device is set will cause the weighted end of the said lever to rise. 4

The rheostat arm (not shown) to be moved by the operation of the device is connected to one end of a piston rod 10 attached to a piston 11, which is operated by suitable fluid pressure as, for instance, water from mains, introduced into the cylinder 12 and controlled by means of a pilot valve 13 shown in section in Fig. 1. The casing of the cylinder 12 is provided with two passages 14 and 15 shown in dotted lines in Fig. 1, by means of which the water is introduced into or exhausted from the opposite ends of the said cylinder as required to move the piston in the direction desired. The pilot valve 13 receives water from an inlet 151 and exhausts the water through an exhaust pipe 16. The pilot valve 13 is bored out as shown at 131 to form a space in which move the two annular valve members 18 and 19 formed upon a stein 17. These two annular p0rtions serve to close various ports and thus control the direction of the flow of fluid through the valve. The pilot valve 13 is counterbored as shown at 20 and an exhaust passage 21 leads from the bottom portion of the cylindrical bore 131 below the valve members to the counterbore or exhaust space 20 above the said annular valve members, thus permitting the water to be exhausted around the valve at certain times. When the valve spindle 17 is moved up, the inlet port 151 is opened and the water under pressure from the city mains is allowed to flow past the valve into the passage 15 which connects with the left hand end of the cylinder 12, thus causing the piston 11 to move toward the right and to move the rheostat arm (not shown). At the same time the movement of the valve spindle 17 opens the passage 14 from the right hand end of the cylinder to the space in the pilot valve below the valve members, thus allowing the exhaust water from the end of the piston to flow out through the passage 14 to the exhaust passage 16.

Upon the downward movement of the valve spindle 17, it will be seen that connection is made between the inlet opening 151 and the passage 14 which leads to the right- 17 the passage leading from the left hand end of the cylinder is connected with the counterbore and the exhaust pipe 16.

The two valve members 18 and 19 and the various openings controlled by the said valve members are proportioned with regard to each other so that there is an intermediate position of the valve members in which the ports .leading to the passages 14 and 15 are closed, and it will be seen that at this time the piston 11 will stand still as the fluid under pressure is not then being admitted to or exhausted from either end of the cylinder. A slight motion in either direction will operate to admit water to one end of the cylinder and to exhaust it from the other and move the piston in one direction or the other according to the direction in which the valve spindle 17 is moved. It will also be seen that the amount of motion imparted to the piston will be dependent upon the amount the various ports are opened and the length of time which they remain open.

The valve spindle 17 is given its movement by means of a yoke 22 pivotally attached at its lower end to the lever arm E and at its upper end to a floating lever 24. The other end of the floating lever 24 is pivoted to the end of one arm 25 of arock shaft 26 which is itself supported in a lug 27 cast integral with the body of the cylinder 12. The arm 25 of the rock shaft 26 acts as a movable fulcrum or point of support for the floating lever 24. The other arm 28 of the said rock shaft 26 is pivotally attached to a connecting rod 29 which is itself attached at 30 to the piston rod 10.

The combination of rock shaft and levers just described acts as a compensating device to retard at the proper intervals the movement of the piston 11 in either .direction. This compensating action is obtained in the following manner. When the weighted lever E rises under an increase in pressure in the system, it moves the yoke 22 upward and lifts the valve stem 17, opening the valve slightly and admitting water under pressure to the left hand end of the cylinder, thus causing the piston 11 to move to the right. The movement of the piston 11 to the right lowers the end of the arm 25 of the rock shaft 26, thus tending to close the valve slightly or to compensate for further upward movement of the lever E and yoke 22. When the pressure in the system again rises sufficiently to lift the lever E farther, the valve spindle 17 is again lifted, moving the piston farther in the same direction, and the piston is again stopped by the further movement of the rock shaft 26. By this means it will be seen that the piston 11 is moved the length of the cylinder or such portion thereof as may be necessary by steps determined by the changes in pressure in the system controlled by the device. The movement in the opposite direction is similarly in steps, each movement of the piston tending to counteract the movement of. the valve lever E which caused it.

By properly proportioning the parts, it is found that a step by step motion may be obtained which is particularly valuable for use in connection with the operation of electric rheostats such as are frequently used for controlling electrically driven pumps for accumulators, elevators or the like.

I claim as my invention:

1. The compensating control device comprising a cylinder and piston, a pilot valve controlling the flow of fluid to the said cylinder, a pressure weighing device movable in re sponse to changes in pressure in the system to be controlled, a floating lever to operate said pilot valve, connections between said pressure weighing device and said floating lever, a movable fulcrum for the said floating lever, and connections to the said piston to move the fulcrum to compensate for the movement of the floating lever caused by the movement of the pressure weighing device.

2. The compensating control device comprising a cylinder and piston, a pilot valve controlling the flow of fluid to the said cylinder, a pressure weighing device movable in response to changes in pressure in the system to be controlled, a floating lever to operate said pilot valve, connections between said pressure weighing device and said floating lever, a rock shaft, one arm of which affords a movable fulcrum for the said floating lever, and connections between the other arm of the said rock shaft and the said piston to move the rock shaft to compensate for the movement of the floating lever caused by the move ment of the pressure weighing device.

In testimony whereof I afliX my signature, in presence of two witnesses.

WILLIAM B. MASON.

Witnesses:

GEORGE P. DIKE, J. HENRY PARKER. 

